1. Field of the Invention
This invention relates to surgical instruments and, in particular, to a locking surgical tool/handle system.
2. Description of the Prior Art
In certain surgical procedures it is necessary to drill or ream the intermedullary canal of a bone. For example, in the replacement of a hip joint, it is very often necessary to replace the natural femoral head with a prosthetic stem affixed within the femur. The procedure for implanting the prosthetic stem includes the use of a broach or rasp in preparing the femoral shaft for the reception of the prosthetic stem by providing contouring of the femoral shaft to the gross geometry of the prosthetic stem, thereby assuring accurate location and good fit. In order to facilitate utilization of such a broach or rasp tool, it has heretofore been suggested that the handle of the instrument be selectively detachable from the working portion of the tool to facilitate precise gauging of the location of the tool within the femoral shaft, to facilitate cleaning of the tool, and for other reasons.
A number of detachable handles for use with releasable tools, such as broaches or rasps, have heretofore been provided. However, prior handles have exhibited a number of problems, one of which being that they fail to achieve a tight fit between the tool and the handle, resulting in a loose or wobbly coupling. This impairs good control of the tool during a surgical procedure. In particular, one such prior handle utilizes a clamping arrangement, wherein the tool has coupling portions which co-act with fixed and movable jaws on a handle, the jaws being operated between locking and unlocking conditions by means of an over-center, lever-operated linkage arrangement. However, because of tolerance variations in the manufacture of the handle components and the broaches, they may not interfit in the locking condition of the handle jaws so as to ensure a tight clamping of the tool to immovably fix it on the handle. The resulting looseness or "play", even though slight, can impair effective tool control.